Internal combustion engine



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March 7, 1939. M. ROTTER INTERNAL COMBUSTION ENGINE Filed-Feb. 12, 1937 2 sheets-sheet 2 Patented Mar. 7, 1939 UNITED STATES PATENT OFFICE INTERNAL COMBUSTION ENGINE United States Application February 12, 1937, Serial No. 125,381

10 Claims.

My invention relates to internal combustion engines, and for the most part to supercharged internal combustion engines and especially to multiple-cylinder supercharged engines employed r in services where the supercharging can be dispensed with at times.

It is especially applicable to the two-cycle fuelinjection engine which exhausts and is airscavenged through. ports in the side wall of the 10 cylinder or cylinders under piston control, but is applicable to other forms of internal combustion engines also as will be apparent.

Generally speaking it provides an improved form of engine and improved valve gear.

15 The invention can be best explained by reference to the accompanying drawings which illustrate one form of it applied to an eight-cylinder Diesel engine of conventional design; its application to other forms of engines will be apparent therefrom. In those drawings, Fig. 1 is a diagrammatic plan View of the engine, partly in section on the lines A-B and C B of Fig. 2, substantially only such parts of the engine being shown however as are necessary for explanation of the invention; i. e. many parts of the engine necessary for its operation arel omitted as will be understood. Fig. 2 is a vertical section on the line II--II of Fig. 1, and Fig. 3 is a section on the line III-III of Fig. 1.

Referring to the drawings: The eight engine cylinders I are mounted in line (Fig. l), and may be water-jacketed or cooled (indicated at 2), in any suitable manner; the pistons 3 drive a common crank shaft (not shown) and the engine can be assumed to be provided with the necessary accessory apparatus, for example suitable liquidfuel injection apparatus and valve gear for each cylinder not shown) that may be driven by an engine-driven cam shaft 4 as usual, etc. The K exhaust passage 5 of each cylinder leads from the side of the cylinder wall somewhat abovethe lowest position of its piston, and likewise each cylinder is charged and may be scavenged through a port or ports E in the cylinder side wall more or less opposite the exhaust port or ports; preferably in the present instance a second port or row of ports l is provided nearer the lowermost or outermost position of the piston for scavenging and charging as illustrated. An air-manifold or receiver 8 for scavenging and low pressure charging extends substantially parallel to the line of cylinders adjacent the port or ports 8, 'I and is provided with non-return valves 9 between these inlet ports' (or between at least the 55 uppermost of these ports 6) and the main body (Cl. 12S-65) of the receiver, there being one or a group of these valves for each cylinder to prevent discharge from, say, the port 6 into the receiver 8 as will be understood; each of these non-return valves may be of the well known form comprising a series of overlapping pivoted louvres I carried in a frame. Preferably the air for scavenging and for the normal or low pressure charging is delivered into the receiver 8 by a positive displacement pump of the kind described below. rI'he location of the ports 5 and 6 (and ports 'I if used) will be understood from prior practices.

A supercharging manifold or receiver I4 is also disposed parallel to the line of cylinders, and preferably immediately above the charging receiver 8; as illustrated, the two receivers may be formed as a single unit. In view of the type of engine illustrated, both the charging and the supercharging mediums in the present instance may be air alone. The supercharging receiver I4 is provided with a port I5 for each cylinder individually, and as customary the ows through these ports are controlled by valves I6 arranged to permit flow of the supercharging medium to each cylinder at the proper stage in its cycle. Preferably these ports or outlet passages I open between non-return valves and cylinder ports serving on occasion to deliver low pressure air to the cylinders; e. g., each port I5 may open between a port '6 and the respective non-return valve 9 therefor as shown in Figs. l and 2. Each non-return valve 9 serves two purposes therefore; first, to prevent the discharge of burned gases from the cylinder into the charging receiver 8 on the outward stroke of the respective piston, and second, to prevent the escape of the supercharging medium into the receiver 8 and direct the same into the cylinder. 'Ihis is a convenient arrangement for providing both charging and supercharging receivers and for providing the necessary connections of the supercharging receiver to the cylinders. It will be understood that the supercharging air is supplied to its receiver I4 at a higher pressure than the charging air in the charging receiver 8. Preferably and as in the case of the charging ,air7 the supercharging air also is supplied by a positive dis'- placement pump. The supercharge-controlling valve I6 may be engine-operated in a customary way; that is to say, each may be provided with a spring I'I tending to hold the valve closed and each may be opened against the spring by an individual adjustable cam lever I8 fulcrumed on an eccentric I9 carried by and fixed to the control rock-shaft 20 and adapted to be actuated in Vby the handle 22, Fig. 1.

properly timed relation by an individual cam 2| on the engine driven cam shaft 4. By turning the shaft 20 and thereby the eccentrics I8 the camlevers or rockersl I8 can be shifted out of the ranges of the cams 2I (position in Fig. 2), or they can be returned more or less deeply into the paths of such cams, thereby varying the Valve stroke which gives more or less supercharging of the engine as may be desired. For this purpose the control shaft 20 may be adjusted automatically, or manually for example as indicated In normal running, without supercharging, the disposition of the exhaust ports 5 with respect to the pistons 3 can be depended on to prevent undue loss of air or charging medium following scavenging, but as has been proposed heretofore the exhaust is stopped more or less, preferably, earlier Vin the compression stroke when supercharging than when not, and to this end I provide, preferably, a valve 25 for each exhaust passage that is held in exhaust-passage-open position when the engine is being operated without supercharging, but which, when supercharging, is engine-operated to more or lessI close the respective exhaust passage on each stroke somewhat before the respective piston 3 closes the exhaust port, thus reducing loss of air. To thisfend each valve 25 may be coupled to the respective rocker arm I8; preferably by coupling each valve stem 26 to one end of a toggle 2'I and 28, the opposite end 29 of which is fixed in position to some part of the machine, and coupling one of the members 21,

. 28 of the toggle to the respective rocker I8, as

. remote from the cam shaft V4, and when the vgagement with the rstern of its valve I8.

rocker I8 is positioned deepest into the pathV of its cam 2I the toggle is broken in the opposite direction (broken line position Fig. 2). A spring 3'I will serve to holdthe rocker in constant en- With this construction the exhaust-controlling valve 25 operates as above described. It may be noted that this valve gearing can be used for a supercharge-exhaust-controlling valve', such as 25, regardless of whether the charging and supercharging receivers, pumps and unloaders illustrated in the drawings areused on the engine, or whether some other form of charging and supercharging apparatus is employed.

For providing the charging medium, which is L understood to be'air in the present instance, and

for producing the pressures required for they re-V ceivers 8 and I4, I preferably employ positive displacement pumps of relatively great Vlength and of correspondingly small transverse dimensions placed Vparallel to the line of cylinders; for example, I prefer to use pumps of the kind shown Vin Schneider U. S. Patent No. 2,021,204'J which Vture as'shown herein, effecting space economy.

According to this invention the advantages of the patent referred to are obtained in a supercharging engineby combining and aligning the super- Vcharging and the low-pressurerpumps. The pump Y supercharge receiverV others the low-pressure pump chambers; for exl ample and as shown the middle compartment and its rotors provide supercharging air for the receiver I4 and the two end compartments and their rotors provide the charging airl for the receiver 8. All the upper rotors 35 (of all the sections) may be aligned and coupled together VVfor driving as a unit, as on a common shaft if desired, in which case all the lower rotors 36 are of course similarly aligned, and both are driven from the engine crank-shaft at their two ends by gearing within the housings 3'I. are so constructed and are driven at such Velocities (regardless of whether driven as units or otherwise) as to deliver respectively the volumes required of them at the respectively appropriate pressures.

The air intake of each of these pumps or pump sections is marked 38 (see Fig. 2 particularly),V

and the air outlets for those which deliver to the receiver 8 are marked 39, while the air outlet for the middlev pump section, which delivers to the I4, is constituted by a duct 40.

In addition to their function of conducting the charging and supercharging air from the pumps to the cylinders, the two receivers 8 and VI4 may also be constructed with a view to providing sui cient capacity to smooth out or absorb pulsations in the pump delivery; as an alternative, the tendency toward pulsations in the inflows can be reduced by dividing each pump transversely into several divisions, and setting the rotors at different ang'les on their shafts, so that the joint effect is a more nearly uniform inflow of the supercharging or charging air; or both these Varrangements may be employed.

, that the supercharging pump or blower is continuously driven. When supercharging air is not needed this pump is unloaded by directing its delivery away from immediate or direct entry into the engine cylinders so thatV it runs idle with no appreciable consumption of power. Preferably I provide a valve or valves directly at the engine for this purpose, such as the two valves 44, which maybe readily connected to and operated by the control system of the engine. Such The rotors 20 Y valves may, for example, open the supercharg` ing receiver I4 to permit the escape of supercharging medium therefrom. This may be allowed to escape wholly to the atmosphere. Preferably however I carrythe escaping supercharg-V ing medium to or adjacent to the intake port or ports 38 of the charging pump or blower andV this is accomplished by the wide passages or-spaces marked 45, each of which extends from one of the valves 44 to a point close to the intake slot 38 of the adjacent charging blower. By thus pro-f viding large and easy escapepassages for the air flow from the supercharging pump, the load on this pump, when the valves 44 are operi,` is` reduced to practically onlyk the load Yof the mechanical friction of thesupercharging pump.V By directing the flow from the supercharger to adjacent the intake ports Vof the charging blower or pump, the' air noise is substantially eliminated,

While such small pressure as may remain in the returned air may be regarded as assistance to the charging pumps. The extension 46 of the charging pump intakes shown in Fig. 2 may lead from one air silencer if desired or it may not be used at all. 'I'he by-pass or unloading valves 44 are held closed while full supercharging is being done; they are held fully open when there is no supercharging, and they occupy proportionate intermediate positions when less than full supercharging is required. Being positioned directly on the engine they are readily controlled in the manner illustrated in Fig. 2, that is to say, they are provided with closing springs such as 41 (Fig. 2) and are placed directly underneath the control rock shaft 20, so that the eccentrics 48 on the latter may be used to open them when supercharging air is not called for. 'I'he camsl or eccentrics 48 may be so shaped that intermediate the two extreme positions they hold the valves 44. in desired intermediate position.

It will be understood that my invention is not limited to the details of construction and operation described above and illustrated in the ac'- companying drawings, except as appears hereinafter in the claims.

I claim:

l. In an internal combustion engine having a plurality of cylinders arranged in aline, a receiver therefor disposed substantially parallel to the line oi' cylinders and means to direct superoharges to the cylinders, the combination therewith of casing means substantially parallel to and co-extensive with the cylinder line, a pluraltiy of rotors in said casing means, said rotors also being disposed substantially parallel to the cylinder line and being of relatively short radius and extended axial dimensions. some of said rotors delivering a gaseous medium to said receiver and some delivering a supercharging gaseous medium at a higher pressure to said means to direct supercharges to the cylinders, and means for driving the rotors at velocities suited to produce the respectively different pressures required of them.

2. 'Ihe subject matter of claim l, characterized by the fact that the supercharging rotors are aligned with the other rotors and the group of rotors as a whole extends continuously for substantially the full length of the line of cylinders.

3. In. an internal combustion engine having a plurality of cylinders arranged in a line and provided with individual charging ports. a charging receiver for said ports disposed substantially parallel to the line of cylinders, and a non-return valve between each of said ports and said receiver. the combination therewith of a supercharging receiver also disposed substantially parallel to said cylinder line and provided with individual outlet passages opening to said charging ports between the interior of the respective cylinder and the respective non-return valve. valves individually controlling the ow through said outlet passages, casing means substantially parallel to and coextensive with the cylinder line, a nlurality of rotors in said casing means also substantially parallel to said line, some of said rotors delivering gaseous medium to said charging receiver and some delivering a gaseous medium at 1cigher pressure to said supercharging receiver, super-charging rotors being aligned with the other rotors and all said rotors being of relatively short radius and the group of rotors as a whole extending continuously for substantially the full length of the line of cylinders, and means for driving the rotors at velocities suited to produce the respectively different pressures required of them.

4. In an internal combustion engine having scavenging and charging means, a supercharger, means to drive the supercharger continuously and a valve operating to time the flow from the supercharger to an engine cylinder direct, the combination therewith oi a by-pass valve to permit the flow from the supercharger to pass away from direct entry into the cylinder, and means to adjust the position of said by-pass valve to control the load on the supercharger.

5. In an internal combustion engine having scavenging and charging means, a supercharger, means at the engine providing a passage to lead the flow from the supercharger into an engine cylinder, means to drive the supercharger continuously and a valve at said passage-providing means operating to time ow from said passage to an engine cylinder, vthe combination therewith of a by-pass valve at said passage-providing means to open the same to permit ow from the superchargers to pass away from direct entry into the cylinder, and means to adjust the position of said by-pass valve to control the load on the supercharger.

6. In an internal combustion engine having scavenging and charging means including a scavenging and charging pump and a supercharger, means to drive the supercharger continuously and a Valve operating to time flow from the supercharger to an engine cylinder direct, the combination therewith of a ley-pass valve to permit the ow from the supercharger to pass away from direct entry into the cylinder, means providing a passage to lead the ow from said valve to a point adjacent the intake of said scavenging and charging pump, and means to adjust the position of said by-pass valve to control the load on the supercharger.

'7. In an internal combustion engine having an exhaust port in a cylinder side wall controlled by the piston, cylinder scavenging and charging means including means to supercharge the cylinder, and an engine-operated valve to control flow from said exhaust port while supercharging, the combination therewith of a by-pass valve to permit the ilow from the supercharging means to pass away from direct entry into the cylinder, and a single means to both adjust the action of said engine-operated exhaust-controlling valve and to control the position of said by-pass valve.

8. In an internal combustion engine having scavenging and charging means including means to supercharge the engine and an engine-operated valve to control the flow from said supercharging means to an engine cylinder direct, the combination therewith of a by-pass valve to permit the llow from the super-charging means to pass away from direct entry into the cylinder, and a single means to both adjust the action of said engine-operated supercharge-controlling valve and to control the position of said by-pass valve.

9. In an internal combustion engine having an exhaust port in a cylinder side wall controlled by the piston, cylinder scavenging and charging means including means to supercharge tbe cylinder and an engine-operated valve to control the ow from said supercharging means to the cylinder direct, and an engine-operated valve to control flow from said exhaust port when supercharging. the combination therewith of a by-pass valve to permit the flow from the supercharging means to pass away from direct entry into the cylinder, and a single means to adjust the actions of both said exhaust-controlling valve and said supercharging-controlling valve and to control the position of said by-pass valve.

' Y 10. VIn anV internal` combustion engine having means for scavenging and charging with a gaseous medium,`means for further charging with a gaseous medium of higher pressure including a Vvalve to control the flow thereof to a cylinder of A the engine, a cam shaft, a member adjustable in Y haust from said cylinder when charging with said higher pressure gaseous medium, the combination therewith of a toggle, one end of Y which is xed andthe other end of which is connected toV said exhaust-controlling valve,'and a link confV necting one of the'members of the toggle torsaid adjustable valve-operating member to operate the exhaust-controlling valve as the higher-pressure controlling valve is operated, said link beingiso related that When said valve-operating member is adjusted toward non-valve-operating position thertoggle is moved thereby toward broken position and thereby the exhaust-controlling valve is adjusted toward open position.

MAX ROT'I'ER. 

